Reverse input prevention clutch

Abstract

This invention provides a reverse input prevention clutch that minimizes vibration when rotation is applied to the input shaft while there is no load on the output shaft. [Solution] A reverse input prevention clutch comprising an output shaft 2 rotatably supported coaxially with an input shaft 1, an annular fixed outer ring 3 surrounding the outer circumference of the output shaft 2, a plurality of divided outer rings 4 arranged along the inner circumference of the fixed outer ring 3, one-sided roller 5a and the other-sided roller 5b positioned between the inner circumference of the divided outer rings 4 and the outer circumference of the output shaft 2, a roller biasing spring 20 incorporated between the one-sided roller 5a and the other-sided roller 5b, and a free-moving connecting part 23 connecting the input shaft 1 and the output shaft 2 with circumferential play, wherein a rotational resistance loading mechanism 26, 27 is provided to load a rotational resistance on the output shaft 2 that is greater than the biasing force acting from the roller biasing spring 20 on the one-sided roller 5a and the other-sided roller 5b.

Description

Technical Field

[0001] The present invention relates to a reverse input prevention clutch. Background Art

[0002] A belt-type continuously variable transmission is known as a transmission for automobiles (see, for example, Patent Document 1). The belt-type continuously variable transmission disclosed in Patent Document 1 includes a driving pulley, a driven pulley, and a transmission belt wound around the driving pulley and the driven pulley. The driving pulley is composed of a fixed sheave having an axially fixed position and a movable sheave that is axially movable by a sheave actuator, and a V-groove around which the transmission belt is wound is formed between the fixed sheave and the movable sheave.

[0003] In this belt-type continuously variable transmission, the width of the V-groove formed between the movable sheave and the fixed sheave can be changed by moving the movable sheave in the axial direction with the sheave actuator. When the width of the V-groove changes, the winding diameter of the transmission belt relative to the driving pulley changes, so the speed ratio of rotation transmitted from the driving pulley to the driven pulley via the transmission belt changes.

[0004] Meanwhile, in the above-described belt-type continuously variable transmission, it is necessary to hold the axial position of the movable sheave against the axial component of the force received from the transmission belt. That is, the movable sheave and the fixed sheave receive a radially inward force from the transmission belt wound around the V-groove, and due to this radially inward force, an axial component force directed to the side away from the fixed sheave acts on the inclined surface of the V-groove of the movable sheave. Therefore, if the axial position of the movable sheave is not held against the axial component of the force received from the transmission belt, the movable sheave will move axially away from the fixed sheave, and the width of the V-groove between the movable sheave and the fixed sheave will increase.

[0005] Therefore, in Patent Document 1, a reverse input prevention clutch is incorporated into the sheave actuator in order to hold the axial position of the movable sheave against the axial component of the force received from the transmission belt.

[0006] In other words, a sheave actuator that moves a movable sheave in the axial direction comprises an electric motor and a motion conversion mechanism that converts the rotation of the electric motor into axial movement of the movable sheave. In Patent Document 1, a reverse input prevention clutch is incorporated into the rotation transmission mechanism that transmits rotation from the electric motor to the motion conversion mechanism. By incorporating a reverse input prevention clutch, when an axial component force acting on the movable sheave away from the fixed sheave is applied, the reverse input prevention clutch receives the rotational force (reverse input torque) transmitted from the movable sheave via the motion conversion mechanism. This makes it possible to maintain the axial position of the movable sheave against the axial component force of the force received from the transmission belt. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2007-263285 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, as described in Patent Document 1, when a reverse input prevention clutch is incorporated into the sheave actuator, a problem has been found in that when the movable sheave is moved axially away from the fixed sheave by the sheave actuator, the movable sheave may not move smoothly.

[0009] In other words, the reverse input prevention clutch of Patent Document 1 comprises an input shaft to which the rotation of an electric motor is input, an output shaft rotatably supported coaxially with the input shaft, an annular fixed outer ring surrounding the outer circumference of the output shaft, a plurality of pairs of rollers incorporated between the cam surface on the outer circumference of the output shaft and the cylindrical surface on the inner circumference of the fixed outer ring, a roller biasing spring that biases each pair of rollers in a direction that causes them to mesh between the cam surface and the cylindrical surface, a roller holder connected to the input shaft so as to rotate integrally with the input shaft, and a free-moving coupling portion that connects the input shaft and the output shaft with circumferential play.

[0010] This reverse input prevention clutch prevents the rollers from jamming between the cam surface and the cylindrical surface. When rotation is applied to the input shaft, the roller retainer, which rotates integrally with the input shaft, presses the rearmost roller in the direction of rotation forward in each pair of rollers. Therefore, the rotation of the input shaft is transmitted to the output shaft via the free-moving coupling, and the output shaft rotates integrally with the input shaft.

[0011] On the other hand, when rotation is input to the output shaft (i.e., when reverse input torque is applied to the reverse input prevention clutch), the cam surface on the outer circumference of the output shaft moves forward in the direction of rotation. As a result, the roller on the rear side of each pair of rollers engages between the cam surface and the cylindrical surface, preventing further rotation of the output shaft, and the output shaft becomes locked. Therefore, the transmission of rotation from the output shaft to the input shaft is prevented.

[0012] Subsequently, when rotation is input to the input shaft again, the roller holder, which rotates integrally with the input shaft, presses the rearmost roller in the direction of rotation forward in each pair of rollers. This disengages the rearmost roller in the direction of rotation, releasing the lock on the output shaft. Then, the rotation of the input shaft is transmitted to the output shaft via the movable coupling, and the output shaft rotates integrally with the input shaft.

[0013] Here, the action of locking the output shaft due to the reverse input (the action of preventing the rotation of the output shaft) is a sudden action caused by the roller directly engaging with the cam surface on the outer circumference of the output shaft and the cylindrical surface on the inner circumference of the fixed outer ring, and the action of releasing the lock of the output shaft is also a sudden action caused by the roller disengaging from the direct engagement between the cam surface on the outer circumference of the output shaft and the cylindrical surface on the inner circumference of the fixed outer ring.

[0014] Therefore, when this reverse input prevention clutch is incorporated into the sheave actuator, there is a problem in that the movement of the movable sheave becomes unstable when the sheave actuator moves the movable sheave axially away from the fixed sheave.

[0015] In other words, when a reverse input prevention clutch is incorporated into a sheave actuator, the axial force acting on the movable sheave from the transmission belt is transmitted to the reverse input prevention clutch via a motion conversion mechanism, so the output shaft of the reverse input prevention clutch is always subjected to reverse input torque.

[0016] On the other hand, when the sheave actuator moves the movable sheave axially away from the fixed sheave, the rotation of the electric motor is input to the input shaft of the reverse input prevention clutch, and the direction of this rotation is the same as the reverse input torque acting on the output shaft of the reverse input prevention clutch.

[0017] Therefore, when a sheave actuator moves a movable sheave axially away from a fixed sheave, a phenomenon may occur in which the output shaft locks due to the rotational speed of the output shaft of the reverse input prevention clutch exceeding the rotational speed of the input shaft, and then the output shaft unlocks due to the rotational speed of the input shaft exceeding the rotational speed of the output shaft, repeating alternately.

[0018] In the reverse input prevention clutch described in Patent Document 1, the output shaft lock operation is a sudden movement due to the direct engagement of the rollers, and similarly, the output shaft unlock operation is also a sudden movement due to the direct disengagement of the rollers. As a result, it was found that the axial movement of the movable sheave away from the fixed sheave becomes an intermittent movement of alternating acceleration and deceleration, which may prevent the movable sheave from moving smoothly.

[0019] Therefore, in order to resolve this problem, the applicant of the present application has already proposed the following configuration as a reverse input prevention clutch with a gradual locking and unlocking operation of the output shaft (Japanese Patent Application No. 2024-35788).

[0020] The input axis to which rotation is input, An output shaft is rotatably supported coaxially with the input shaft, An annular fixed outer ring surrounding the outer circumference of the output shaft, A plurality of segmented outer rings are arranged in a circumferential direction along the inner circumference of the fixed outer ring, A plurality of one-sided rollers and a plurality of other-sided rollers are arranged alternately in the circumferential direction between the inner circumference of the plurality of divided outer rings and the outer circumference of the output shaft, On the outer circumference of the output shaft, a plurality of one-sided cam surfaces are alternately formed in the circumferential direction, forming a wedge-shaped space that narrows toward one side in the circumferential direction between it and the divided outer ring, and a plurality of other-sided cam surfaces are alternately formed in the circumferential direction between it and the divided outer ring, forming a wedge-shaped space that narrows toward the other side in the circumferential direction. The one-side roller is positioned between the one-side cam surface and the divided outer ring, and the other-side roller is positioned between the other-side cam surface and the divided outer ring. A roller biasing spring is incorporated between the one roller and the other roller in a circumferentially compressed state, biasing the one roller and the other roller in a direction away from each other. The input shaft is provided with a other-side roller pressing portion that moves together with the input shaft when the input shaft rotates in one direction in the circumferential direction to push the other-side roller in one direction in the circumferential direction, and a one-side roller pressing portion that moves together with the input shaft when the input shaft rotates in the other direction in the circumferential direction to push the one-side roller in the other direction in the circumferential direction. A reverse input prevention clutch is provided with a free-moving coupling portion between the input shaft and the output shaft, which connects the two with circumferential play.

[0021] In this configuration of the reverse input prevention clutch, when rotation is input to the input shaft in one direction in the circumferential direction, the other side roller pressing part, which moves integrally with the input shaft, pushes the other side roller in the circumferential direction, preventing the other side roller from engaging with the other side roller between the other side cam surface on the outer circumference of the output shaft and the split outer ring. When the input shaft rotates in one direction in the circumferential direction beyond the range of circumferential play of the free-moving coupling, the rotation of the input shaft is transmitted to the output shaft via the free-moving coupling, and the output shaft rotates integrally with the input shaft in one direction in the circumferential direction. Similarly, when rotation is input to the input shaft in the other direction in the circumferential direction, the output shaft rotates integrally with the input shaft in the other direction in the circumferential direction.

[0022] On the other hand, when rotation to one circumferential side is input to the output shaft (that is, when reverse input torque acts), the other-side cam surface on the outer circumference of the output shaft moves toward the one circumferential side, so the other-side roller is caught between the other-side cam surface on the outer circumference of the output shaft and the split outer ring, the split outer ring is pressed radially outward by the catching of the other-side roller, the outer circumference of the split outer ring frictionally engages with the inner circumference of the fixed outer ring, the rotation of the output shaft toward the one circumferential side is braked by the frictional engagement, and the output shaft is brought into a locked state. Therefore, transmission of rotation from the output shaft to the input shaft is blocked.

[0023] Thereafter, when rotation to one circumferential side is input to the input shaft, the other-side roller pressing portion that moves integrally with the input shaft presses the other-side roller toward the one circumferential side, so the catching of the other-side roller between the other-side cam surface on the outer circumference of the output shaft and the split outer ring is released, the frictional engagement between the outer circumference of the split outer ring and the inner circumference of the fixed outer ring is canceled, rotation of the output shaft toward the one circumferential side is allowed by the cancellation of the frictional engagement, and the output shaft is brought into an unlocked state. Thereafter, rotation of the input shaft is transmitted to the output shaft via the idle coupling portion, and the output shaft rotates integrally with the input shaft toward the one circumferential side.

[0024] Similarly, when rotation to the other circumferential side is input to the output shaft, the one-side roller is caught between the one-side cam surface on the outer circumference of the output shaft and the split outer ring, the split outer ring is pressed radially outward by the catching of the one-side roller, the outer circumference of the split outer ring frictionally engages with the inner circumference of the fixed outer ring, and rotation of the output shaft toward the other circumferential side is braked by the frictional engagement. Then, when rotation to the other circumferential side is input to the input shaft thereafter, the one-side roller pressing portion presses the one-side roller toward the other circumferential side, so the catching of the one-side roller between the one-side cam surface on the outer circumference of the output shaft and the split outer ring is released, the frictional engagement between the outer circumference of the split outer ring and the inner circumference of the fixed outer ring is canceled, and the output shaft rotates integrally with the input shaft toward the other circumferential side.

[0025] Here, when rotation is input to the output shaft (i.e., when reverse input torque is applied to the reverse input prevention clutch), instead of directly engaging the roller between the cam surface on the outer circumference of the output shaft and the inner circumference of the fixed outer ring, one side roller or the other side roller is engaged between the cam surface on the outer circumference of the output shaft and the split outer ring, and the outer circumference of the split outer ring is frictionally engaged with the inner circumference of the fixed outer ring to brake the rotation of the output shaft, so the locking operation of the output shaft is gradual. Similarly, when unlocking the output shaft, the frictional engagement between the outer circumference of the split outer ring and the inner circumference of the fixed outer ring is released, allowing the output shaft to rotate, so the unlocking operation of the output shaft is gradual compared to the case where the direct engagement of the roller between the cam surface on the outer circumference of the output shaft and the inner circumference of the fixed outer ring is released.

[0026] Therefore, when this reverse input prevention clutch configuration is used in a sheave actuator, when the sheave actuator moves the movable sheave axially away from the fixed sheave, the axial movement of the movable sheave is less likely to be an intermittent motion of alternating acceleration and deceleration, allowing the movable sheave to move smoothly.

[0027] As described above, a reverse input prevention clutch, which has multiple segmented outer rings arranged along the inner circumference of a fixed outer ring, locks the output shaft by frictionally engaging the outer circumference of the segmented outer rings with the inner circumference of the fixed outer ring when a reverse input torque is applied to the output shaft. This has the advantage that the locking and unlocking operations of the output shaft are gradual.

[0028] Incidentally, when the inventors of the present invention prototyped and evaluated the aforementioned reverse input prevention clutch, they encountered a problem in which vibration occurred when rotation was applied to the input shaft while there was no load on the output shaft.

[0029] Therefore, the inventors investigated the cause of this vibration and found that it was generated by the following mechanism.

[0030] In other words, as shown in Figure 7(a), the reverse input prevention clutch comprises a fixed outer ring 3, a plurality of divided outer rings 4 arranged circumferentially along the inner circumference of the fixed outer ring 3, a one-sided roller 5a and a other-sided roller 5b positioned between the inner circumference of the divided outer rings 4 and the outer circumference of the output shaft, a roller biasing spring 20 incorporated between the one-sided roller 5a and the other-sided roller 5b in a circumferentially compressed state, a column portion 21 that rotates integrally with the input shaft (not shown), and a free-moving connecting portion 23 that connects the input shaft and the output shaft 2 with circumferential play. The free-moving connecting portion 23 consists of a recess 24 that rotates integrally with the input shaft and a protrusion 25 that rotates integrally with the output shaft 2, and the protrusion 25 and the recess 24 are engaged with a circumferential gap.

[0031] In this reverse input prevention clutch, when rotation is input to the input shaft (not shown), first, as shown by the arrow in Figure 7(b), the column portion 21 moves circumferentially together with the input shaft, and the column portion 21 pushes the roller 5b on the rear side (left side in the figure) in the direction of rotation forward (right side in the figure), causing the rear roller 5b in the direction of rotation to compress the roller biasing spring 20. When the roller biasing spring 20 is compressed, the force with which the roller biasing spring 20 presses the roller 5a on the front side (right side in the figure) in the direction of rotation increases, and as shown by the arrow in Figure 7(c), the force with which the front roller 5a in the direction of rotation presses against the cam surface 19a on the outer circumference of the output shaft 2 causes the output shaft 2 to start rotating. At this time, as shown in Figures 7(b) and (c), the convex portion 25 and concave portion 24 of the free-moving coupling portion 23 move relative to each other in the circumferential direction due to the rotation of the input shaft, but they do not come into contact. Then, as the output shaft 2 begins to rotate, as shown in Figure 7(c), the front roller 5a in the direction of rotation moves forward (to the right in the figure) along with the output shaft 2, causing the roller biasing spring 20 to extend. This reduces the force with which the front roller 5a presses against the cam surface 19a, and the rear roller 5b in the direction of rotation engages between the split outer ring 4 and the output shaft 2, stopping the rotation of the output shaft 2. Subsequently, as shown by the arrow in Figure 7(b), the rear roller 5b in the direction of rotation is pushed forward (to the right in the figure) by the column 21, and as shown in Figure 7(c), the force with which the front roller 5a presses against the cam surface 19a causes the output shaft 2 to begin rotating. It was found that vibration occurs when rotation is applied to the input shaft while the output shaft 2 is unloaded (no-load state) due to the repetition of the above operation.

[0032] The problem this invention aims to solve is to provide a reverse input prevention clutch that is less prone to vibration when rotation is applied to the input shaft while no load is applied to the output shaft. [Means for solving the problem]

[0033] To solve the above problems, this invention provides a reverse input prevention clutch with the following configuration. [Configuration 1] The input axis to which rotation is input, An output shaft is rotatably supported coaxially with the input shaft, An annular fixed outer ring surrounding the outer circumference of the output shaft, A plurality of segmented outer rings are arranged in a circumferential direction along the inner circumference of the fixed outer ring, A plurality of one-sided rollers and a plurality of other-sided rollers are arranged alternately in the circumferential direction between the inner circumference of the plurality of divided outer rings and the outer circumference of the output shaft, On the outer circumference of the output shaft, a plurality of one-sided cam surfaces are alternately formed in the circumferential direction, forming a wedge-shaped space that narrows toward one side in the circumferential direction between it and the divided outer ring, and a plurality of other-sided cam surfaces are alternately formed in the circumferential direction between it and the divided outer ring, forming a wedge-shaped space that narrows toward the other side in the circumferential direction. The one-side roller is positioned between the one-side cam surface and the divided outer ring, and the other-side roller is positioned between the other-side cam surface and the divided outer ring. A roller biasing spring is incorporated between the one roller and the other roller in a circumferentially compressed state, biasing the one roller and the other roller in a direction away from each other. The input shaft is provided with a other-side roller pressing portion that moves together with the input shaft when the input shaft rotates in one direction in the circumferential direction to push the other-side roller in one direction in the circumferential direction, and a one-side roller pressing portion that moves together with the input shaft when the input shaft rotates in the other direction in the circumferential direction to push the one-side roller in the other direction in the circumferential direction. A movable coupling is provided between the input shaft and the output shaft, connecting them with circumferential play. A reverse input prevention clutch is provided with a rotational resistance loading mechanism that loads a rotational resistance on the output shaft that is greater than the biasing force acting on one roller and the other roller from the roller biasing spring.

[0034] This configuration includes a rotational resistance loading mechanism that applies rotational resistance to the output shaft. This prevents the output shaft from starting to rotate when rotation is applied to the input shaft while no load is applied to the output shaft, due to the force of the front roller pressing against the cam surface in the direction of rotation. Instead, the output shaft starts to rotate through rotational transmission from the input shaft to the output shaft via the movable coupling. Therefore, it is possible to prevent vibration from occurring when rotation is applied to the input shaft while no load is applied to the output shaft.

[0035] [Configuration 2] An input-side housing is assembled to which an input-side bearing that rotatably supports the input shaft is fitted, It comprises an output-side housing into which an output-side bearing is assembled to rotatably support the output shaft, The reverse input prevention clutch according to configuration 1, wherein the rotational resistance load mechanism comprises a preloading elastic member incorporated in a state of elastic compression deformation in the axial direction, and a thrust rolling bearing that applies the starting torque generated when the elastic restoring force of the preloading elastic member is applied as the rotational resistance to the output shaft.

[0036] By adopting this configuration, a rotational resistance loading mechanism is employed that applies rotational resistance with almost no wear, making it possible to use the reverse input prevention clutch for high-speed rotation applications. That is, as a rotational resistance loading mechanism that applies rotational resistance to the output shaft, for example, it is possible to adopt a configuration in which a sliding contact member that slides against the output shaft is provided and rotational resistance is applied to the output shaft by the friction of the sliding contact member, but if a rotational resistance loading mechanism with such a configuration is adopted, wear of the sliding contact member progresses rapidly, so it cannot be used for applications in which the reverse input prevention clutch is rotated at high speeds. In contrast, by adopting a rotational resistance loading mechanism consisting of a preloading elastic member that is incorporated in a state of elastic compression deformation in the axial direction, and a thrust rolling bearing that applies the starting torque generated when the elastic restoring force of the preloading elastic member is applied as rotational resistance to the output shaft, the starting torque of the rolling bearing is used as rotational resistance, so almost no wear occurs, making it possible to use the reverse input prevention clutch for high-speed rotation applications.

[0037] [Configuration 3] The reverse input prevention clutch according to configuration 1 or 2, wherein the magnitude of the rotational resistance applied to the output shaft by the rotational resistance load mechanism is set to be greater than the circumferential biasing force acting on the one roller and the other roller from the roller biasing spring when the input shaft is rotated relative to the output shaft until the circumferential play of the free coupling portion is eliminated.

[0038] By adopting this configuration, when rotation is applied to the input shaft while there is no load on the output shaft, the circumferential play in the free-moving coupling is eliminated, making it possible to reliably prevent the output shaft from starting to rotate due to the force exerted by the roller on the front side in the direction of rotation pressing against the cam surface before the output shaft begins to rotate.

[0039] [Structure 4] A reverse input prevention clutch according to any one of configurations 1 to 3, wherein the circumferential end face of each divided outer ring is inclined with respect to the axial direction such that the boundary between adjacent divided outer rings in the circumferential direction extends diagonally with respect to the axial direction.

[0040] By adopting this configuration, the boundaries between the divided outer rings extend diagonally to the axial direction rather than parallel to the axial direction, making it possible to suppress vibrations when one roller or the other roller crosses over the boundary between the divided outer rings.

[0041] [Composition 5] A reverse input prevention clutch according to any one of configurations 1 to 4, wherein the circumferential length of each divided outer ring is set such that two or more of the one-side rollers and two or more of the other-side rollers are located radially inward of each divided outer ring.

[0042] With this configuration, two or more rollers on one side and two or more rollers on the other side are located radially inward of each divided outer ring. Therefore, when a reverse input torque acts on the output shaft, two or more rollers on one side or two or more rollers on the other side engage between the outer circumference of the output shaft and the divided outer ring, and two or more rollers spaced apart in the circumferential direction press one divided outer ring radially outward. As a result, the frictional engagement between the outer circumference of the divided outer ring and the inner circumference of the fixed outer ring becomes stable.

[0043] [Composition 6] A reverse input prevention clutch according to any one of configurations 1 to 5, wherein a centering portion is provided between the shaft end of the input shaft and the shaft end of the output shaft to maintain the radial relative position of both shaft ends.

[0044] By adopting this configuration, the centering section ensures that the axis of the input shaft and the axis of the output shaft are reliably aligned. This stabilizes the relative positional relationship between the one-sided roller pressing section and the other-sided roller pressing section, and between the one-sided cam surface and the other-sided cam surface, resulting in a stable unlocking operation of the output shaft.

[0045] [Composition 7] Multiple planes, each shaped like a linear cutout of a portion of the outer circumference of the output shaft, are formed circumferentially on the outer circumference of the output shaft, The reverse input prevention clutch according to any one of configurations 1 to 6, wherein the one-sided cam surface and the other-sided cam surface are a portion on one side in the circumferential direction and a portion on the other side in the circumferential direction, respectively, of the circumferential center of each plane.

[0046] By adopting this configuration, it becomes possible to form one cam surface and the other cam surface with high precision at a low cost. [Effects of the Invention]

[0047] The reverse input prevention clutch of this invention is equipped with a rotational resistance loading mechanism that applies rotational resistance to the output shaft. Therefore, when rotation is applied to the input shaft while there is no load on the output shaft, the force of the front roller in the direction of rotation pressing against the cam surface prevents the output shaft from starting to rotate. Instead, the rotation is transmitted from the input shaft to the output shaft via the free-moving coupling, allowing the output shaft to start rotating. As a result, it is possible to prevent vibration from occurring when rotation is applied to the input shaft while there is no load on the output shaft. [Brief explanation of the drawing]

[0048] [Figure 1] Cross-sectional view of a reverse input prevention clutch according to an embodiment of this invention. [Figure 2] Cross-sectional view along line II-II in Figure 1 [Figure 3] Figure 1 shows an exploded perspective view of the input shaft, split outer ring, and output shaft. [Figure 4] Enlarged view of the vicinity of the rotational resistance load mechanism in Figure 1. [Figure 5] A magnified view of a portion of Figure 2. [Figure 6] Figure 5 shows the state where the input shaft shown in Figure 1 is rotated in one direction in the circumferential direction. [Figure 7] (a) is a diagram showing the reverse input prevention clutch of the comparative example in which no rotation is input to the input shaft and no load is applied to the output shaft; (b) is a diagram showing the state in which the roller biasing spring is compressed when rotation is input to the input shaft shown in (a); and (c) is a diagram showing the state in which the output shaft begins to rotate when the front roller in the direction of rotation shown in (b) presses against the cam surface. [Modes for carrying out the invention]

[0049] Figure 1 shows a reverse input prevention clutch according to an embodiment of the present invention. This reverse input prevention clutch comprises an input shaft 1 to which rotation is input, an output shaft 2 rotatably supported coaxially with the input shaft 1, an annular fixed outer ring 3 surrounding the outer circumference of the output shaft 2, a plurality of partially annular segmented outer rings 4 incorporated between the inner circumference of the fixed outer ring 3 and the outer circumference of the output shaft 2, and one-sided rollers 5a and the other-sided rollers 5b (see Figure 2) incorporated between the inner circumference of the segmented outer rings 4 and the outer circumference of the output shaft 2.

[0050] The axial direction is the direction parallel to the central axis of the input shaft 1 (the central axis of rotation), the radial direction is the direction perpendicular to the central axis of the input shaft 1, and the circumferential direction is the direction along the circumference of the circle centered on the central axis of the input shaft 1.

[0051] The input shaft 1 is rotatably supported by an input-side bearing 7 mounted on an input-side housing 6, and the output shaft 2 is rotatably supported by an output-side bearing 9 mounted on an output-side housing 8. A deep groove ball bearing is used for both the input-side bearing 7 and the output-side bearing 9. The axial relative movement of the input-side bearing 7 with respect to the input-side housing 6 is restricted by a retaining ring 10 mounted on the inner circumference of the input-side housing 6, and the axial relative movement of the input shaft 1 with respect to the input shaft 1 is restricted by a retaining ring 11 mounted on the outer circumference of the input shaft 1.

[0052] The output bearing 9 is also restricted from axial relative movement relative to the output housing 8 by a retaining ring 12 mounted on the inner circumference of the output housing 8, and its axial relative movement relative to the output shaft 2 is restricted by a retaining ring 13 mounted on the outer circumference of the output shaft 2. Here, the retaining ring 12 is provided on the side of the input shaft 1 (left side in the figure) relative to the output bearing 9, and the retaining ring 13 is provided on the opposite side of the output bearing 9 from the input shaft 1 (right side in the figure). These retaining rings 12 and 13 prevent the output shaft 2 from moving axially toward the input shaft 1 (left side in the figure) due to the axial load acting on the output shaft 2 from the preloading elastic member 26, which will be described later.

[0053] A centering section 14 is provided between the shaft end of the input shaft 1 and the shaft end of the output shaft 2 to maintain the radial relative position of both shaft ends. In this case, the centering section 14 consists of an axial projection provided at the radial center of one of the shaft ends of the input shaft 1 or the output shaft 2 (the shaft end of the output shaft 2 in the figure) and an axial recess provided at the radial center of the other shaft end (the shaft end of the input shaft 1 in the figure). By fitting the axial projection and the axial recess so as to be rotatable relative to each other, the radial relative position of the shaft ends of the input shaft 1 and the output shaft 2 is maintained. In the figure, the axial projection is provided at the shaft end of the output shaft 2 and the axial recess is provided at the shaft end of the input shaft 1, but it is also possible to adopt a configuration in which the axial projection and the axial recess are swapped.

[0054] The fixed outer ring 3 is a non-rotating member designed to prevent rotation. Here, the fixed outer ring 3 is formed integrally with the output side housing 8, but the fixed outer ring 3 may also be formed separately from the output side housing 8 and fixed to the output side housing 8.

[0055] An inner circumferential friction surface 15 is formed on the inner circumference of the fixed outer ring 3, facing radially from the outer circumference of the divided outer ring 4. The inner circumferential friction surface 15 is an annular surface that is continuous in the circumferential direction over its entire circumference. Here, the inner circumferential friction surface 15 employs a cylindrical surface with a constant inner diameter along the axial direction. The cylindrical center of the inner circumferential friction surface 15 coincides with the center of the output shaft 2.

[0056] As shown in Figure 2, an outer peripheral friction surface 16 is formed on the outer circumference of the divided outer ring 4. The outer peripheral friction surface 16 is the surface that frictionally engages with the inner peripheral friction surface 15 of the fixed outer ring 3 when the divided outer ring 4 is pressed radially outward by the engagement of one side roller 5a or the other side roller 5b. The outer peripheral friction surface 16 is a surface that extends circumferentially over an angular range corresponding to a part of the circumference, and in this case, it is a partial cylindrical surface obtained by dividing a cylindrical surface in the circumferential direction. The radius of curvature of the outer peripheral friction surface 16 is set to be between 97% and 100% of the radius of the inner peripheral friction surface 15 of the fixed outer ring 3. On the inner circumference of the divided outer ring 4, a partially cylindrical divided inner peripheral surface 17 is formed, having the center of curvature at the same position as the center of curvature of the outer peripheral friction surface 16.

[0057] Multiple segmented outer rings 4 are provided so as to be arranged circumferentially along the entire circumference of the inner friction surface 15 of the fixed outer ring 3. All of the segmented outer rings 4 are identical in shape, and the circumferential lengths of each segmented outer ring 4 are equal to each other. The circumferential length of each segmented outer ring 4 is such that two or more (two or three in the figure) rollers 5a on one side and two or more (two or three in the figure) rollers 5b on the other side are located radially inward of each segmented outer ring 4. In the figure, the central angle of each segmented outer ring 4 is set to be the size obtained by dividing 360° into three equal parts in the circumferential direction (specifically, a size of 117° to 120°), but the central angle of each segmented outer ring 4 may also be the size obtained by dividing 360° into four equal parts in the circumferential direction (specifically, a size of 87° to 90°).

[0058] As shown in Figure 2, each segmented outer ring 4 is arranged adjacent to each other in the circumferential direction with a small gap between them to allow radial movement of each segmented outer ring 4 (movement to frictionally engage the outer peripheral friction surface 16 shown in Figure 5 with the inner peripheral friction surface 15). As shown in Figure 3, the circumferential end faces 18 of each segmented outer ring 4 are inclined with respect to the axial direction so that the boundaries between adjacent segmented outer rings 4 extend diagonally with respect to the axial direction.

[0059] As shown in Figure 5, the outer circumference of the output shaft 2 has alternating cam surfaces 19a and 19b formed in the circumferential direction. The cam surface 19a faces radially opposite the divided inner circumferential surface 17 of the divided outer ring 4, forming a wedge-shaped space between it and the divided inner circumferential surface 17 that gradually narrows toward one side in the circumferential direction (right side in the figure). The cam surface 19b also faces radially opposite the divided inner circumferential surface 17 of the divided outer ring 4, forming a wedge-shaped space between it and the divided inner circumferential surface 17 that gradually narrows toward the other side in the circumferential direction (left side in the figure). The cam surface 19a and the cam surface 19b here are the parts on one side in the circumferential direction and the parts on the other side in the circumferential direction of a plane shaped like a straight line cut out from a part of the outer circumference of the output shaft 2 when viewed from the axial direction.

[0060] The roller 5a on one side and the roller 5b on the other side are arranged alternately in the circumferential direction, corresponding to the cam surface 19a on one side and the cam surface 19b on the other side. The roller 5a on one side is positioned between the cam surface 19a on one side and the divided inner circumferential surface 17 of the divided outer ring 4, and the roller 5b on the other side is positioned between the cam surface 19b on the other side and the divided inner circumferential surface 17 of the divided outer ring 4. Both the roller 5a on one side and the roller 5b on the other side are rollers with cylindrical surfaces, and are assembled with their roller axes oriented axially. The diameter of the roller 5a on one side and the diameter of the roller 5b on the other side are equal.

[0061] A roller biasing spring 20 is provided between one side roller 5a and the other side roller 5b. The roller biasing spring 20 is incorporated between the one side roller 5a and the other side roller 5b in a circumferentially compressed state, and its elastic restoring force biases the one side roller 5a and the other side roller 5b away from each other. Due to the biasing force of this roller biasing spring 20, the one side roller 5a is in a state where it is simultaneously in contact with the one side cam surface 19a and the divided inner circumferential surface 17 of the divided outer ring 4, and the other side roller 5b is also in a state where it is simultaneously in contact with the other side cam surface 19b and the divided inner circumferential surface 17 of the divided outer ring 4.

[0062] As shown in Figure 2, multiple rollers 5a are provided on one side, corresponding to the number of cam surfaces 19a on one side (eight in the figure), and multiple rollers 5b are also provided on the other side, corresponding to the number of cam surfaces 19b on the other side (eight in the figure).

[0063] As shown in Figures 1 and 2, the input shaft 1 is provided with a column portion 21 that extends axially between the outer circumference of the output shaft 2 and the inner circumference of the divided outer ring 4. As shown in Figures 1 and 3, the column portion 21 is connected to the input shaft 1 so as to move circumferentially together with the input shaft 1 when the input shaft 1 rotates. In Figures 1 and 3, the column portion 21 is formed integrally with the input shaft 1, but the column portion 21 may be formed separately from the input shaft 1 and fixed to the input shaft 1.

[0064] As shown in Figure 5, each column portion 21 is positioned in the circumferential direction opposite to one side (right side in the figure) of the one-side roller 5a and corresponding to the other side (left side in the figure) of the other-side roller 5b. Here, the other end (left end in the figure) of the column portion 21 opposite to one side (right side in the figure) of the one-side roller 5a constitutes the one-side roller pressing portion 22a, and the other end (right end in the figure) of the column portion 21 opposite to the other side (left side in the figure) of the other-side roller 5b constitutes the other-side roller pressing portion 22b. The one-side roller pressing portion 22a is the part that moves together with the input shaft 1 when the input shaft 1 rotates in the other circumferential direction (left side in the figure) and pushes the one-side roller 5a in the other circumferential direction (left side in the figure), and the other-side roller pressing portion 22b is the part that moves together with the input shaft 1 when the input shaft 1 rotates in one circumferential direction (right side in the figure) and pushes the other-side roller 5b in the one circumferential direction (right side in the figure). The one-side roller pressing portion 22a faces the one circumferential side (right side in the figure) of the one-side roller 5a with a small gap between them, and the other-side roller pressing portion 22b also faces the other circumferential side (left side in the figure) of the other-side roller 5b with a small gap between them.

[0065] As shown in Figures 1 and 2, a movable coupling portion 23 is provided between the input shaft 1 and the output shaft 2, connecting them with circumferential play. In this case, the movable coupling portion 23 consists of a recess 24 provided on the input shaft 1 and a protrusion 25 provided on the output shaft 2 (in the figures, the protruding part of a pin press-fitted into a round hole). As shown in Figures 5 and 6, the protrusion 25 engages with the recess 24 with a circumferential gap.

[0066] The movable coupling portion 23 allows the input shaft 1 to rotate relative to the output shaft 2 when the input shaft 1 shown in Figure 1 rotates relative to the output shaft 2, as long as the rotation angle of the input shaft 1 with respect to the output shaft 2 is within the range of circumferential play (the circumferential gap between the convex portion 25 and the concave portion 24 shown in Figure 5), and no transmission of rotation from the input shaft 1 to the output shaft 2 occurs. On the other hand, when the rotation angle of the input shaft 1 with respect to the output shaft 2 exceeds the range of circumferential play (the circumferential gap between the convex portion 25 and the concave portion 24 shown in Figure 5), the concave portion 24 comes into contact with the convex portion 25, thereby transmitting the rotation of the input shaft 1 to the output shaft 2, and the input shaft 1 and the output shaft 2 are connected in such a way that the output shaft 2 rotates integrally with the input shaft 1.

[0067] The amount of circumferential play in the movable coupling portion 23 (the size of the circumferential gap between the convex portion 25 and the concave portion 24 shown in Figure 5) is set so that when the column portion 21 shown in Figure 5 rotates integrally with the input shaft 1 shown in Figure 1 to one side in the circumferential direction (to the right in the figure), and the other side roller pressing portion 22b shown in Figure 5 contacts the other side roller 5b, the inner end surface of the concave portion 24 in the circumferential direction does not yet contact the convex portion 25, leaving circumferential play. Similarly, when the column portion 21 shown in Figure 5 rotates integrally with the input shaft 1 shown in Figure 1 to the other side in the circumferential direction (to the left in the figure), and the one side roller pressing portion 22a shown in Figure 5 contacts the one side roller 5a, the inner end surface of the concave portion 24 in the circumferential direction does not yet contact the convex portion 25, leaving circumferential play. Here, the concave portion 24 is provided on the input shaft 1 and the convex portion 25 is provided on the output shaft 2, but this can also be reversed, with the convex portion 25 provided on the input shaft 1 and the concave portion 24 on the output shaft 2.

[0068] As shown in Figure 4, a preloading elastic member 26 is incorporated between the output shaft 2 and the output side housing 8 in a state of elastic compression deformation in the axial direction. A thrust rolling bearing 27 is also incorporated between the preloading elastic member 26 and the output side housing 8, and the elastic restoring force (axial load) of the preloading elastic member 26 is applied to the thrust rolling bearing 27. A stepped portion 28 (retaining ring in the figure) is provided on the outer circumference of the output shaft 2 to axially support one end of the preloading elastic member 26 in the axial direction.

[0069] The output shaft 2 is subjected to a rotational resistance load of the thrust rolling bearing 27, which is generated by the axial load applied to the thrust rolling bearing 27 by the preloading elastic member 26. The magnitude of this rotational resistance is greater than the biasing force acting from the roller biasing spring 20 on one side roller 5a and the other side roller 5b in the state shown in Figure 5 (i.e., the torque due to the force acting from each roller biasing spring 20 on each side roller 5a (or each other side roller 5b) as shown in Figure 2). In other words, the preloading elastic member 26 and the thrust rolling bearing 27 shown in Figure 4 constitute a rotational resistance load mechanism that loads the output shaft 2 with a rotational resistance greater than the biasing force acting from the roller biasing spring 20 on one side roller 5a and the other side roller 5b as shown in Figure 2.

[0070] The magnitude of the rotational resistance applied to the output shaft 2 by the preloading elastic member 26 and the thrust rolling bearing 27 shown in Figure 4 is preferably set to be greater than the circumferential biasing force acting on one roller 5a and the other roller 5b from the roller biasing spring 20 when the input shaft 1 is rotated relative to the output shaft 2 until there is no circumferential play in the free-moving coupling portion 23 (i.e., the recess 24 contacts the convex portion 25), as shown in Figure 6.

[0071] As shown in Figure 4, a thrust ball bearing can be used as the thrust rolling bearing 27, but a thrust needle roller bearing is preferable because it can achieve both sufficient starting torque for the bearing and space saving. Furthermore, as the preloading elastic member 26, a rubber ring member can be used, but a metal spring such as a compression coil spring, disc spring, or wave spring is preferable because it can ensure durability.

[0072] As shown in Figure 6, when rotation is input to the input shaft 1 in one circumferential direction (to the right in the figure), the reverse input prevention clutch prevents the other side roller 5b from engaging with the other side roller 5b between the other side cam surface 19b on the outer circumference of the output shaft 2 and the split outer ring 4. When the input shaft 1 rotates in one circumferential direction (to the right in the figure) beyond the range of circumferential play of the free coupling part 23, the rotation of the input shaft 1 is transmitted to the output shaft 2 via the free coupling part 23, causing the output shaft 2 to rotate in one circumferential direction (to the right in the figure) together with the input shaft 1. Similarly, when rotation is input to the input shaft 1 in the other circumferential direction (to the left in the figure), the output shaft 2 also rotates in the other circumferential direction (to the left in the figure) together with the input shaft 1.

[0073] On the other hand, when rotation is input to the output shaft 2 shown in Figure 5 in one circumferential direction (to the right in the figure) (i.e., when a reverse input torque is applied), the other cam surface 19b on the outer circumference of the output shaft 2 moves to the other circumferential direction (to the right in the figure). As a result, the other roller 5b engages between the other cam surface 19b on the outer circumference of the output shaft 2 and the split outer ring 4. This engagement of the other roller 5b presses the split outer ring 4 radially outward, causing the partially annular outer circumferential friction surface 16 of the split outer ring 4 to frictionally engage with the annular inner circumferential friction surface 15 of the fixed outer ring 3. This frictional engagement brakes the rotation of the output shaft 2 to one circumferential direction (to the right in the figure), and the output shaft 2 becomes locked. Therefore, the transmission of rotation from the output shaft 2 to the input shaft 1 is prevented.

[0074] Subsequently, when rotation is input to the input shaft 1 in one circumferential direction (to the right in the figure), the other roller pressing part 22b, which moves integrally with the input shaft 1, presses the other roller 5b in one circumferential direction (to the right in the figure). As shown in Figure 6, the engagement of the other roller 5b between the other cam surface 19b on the outer circumference of the output shaft 2 and the split outer ring 4 is released, and the frictional engagement between the outer friction surface 16 of the split outer ring 4 and the inner friction surface 15 of the fixed outer ring 3 is released. This release of frictional engagement allows the output shaft 2 to rotate in one circumferential direction (to the right in the figure), and the lock on the output shaft 2 is released. Subsequently, the rotation of the input shaft 1 is transmitted to the output shaft 2 via the floating coupling part 23, and the output shaft 2 rotates integrally with the input shaft 1 in one circumferential direction (to the right in the figure).

[0075] Similarly, when rotation is input to the output shaft 2 in the other circumferential direction (left side in the figure) as shown in Figure 5, the one-side roller 5a engages between the one-side cam surface 19a on the outer circumference of the output shaft 2 and the divided outer ring 4. This engagement of the one-side roller 5a presses the divided outer ring 4 radially outward, causing the partially annular outer circumferential friction surface 16 of the divided outer ring 4 to frictionally engage with the annular inner circumferential friction surface 15 of the fixed outer ring 3. This frictional engagement brakes the rotation of the output shaft 2 in the other circumferential direction (left side in the figure). Then, when rotation is input to the input shaft 1 in the other circumferential direction (left side in the diagram), the one-side roller pressing part 22a presses the one-side roller 5a in the other circumferential direction (left side in the diagram), disengaging the one-side roller 5a from the one-side cam surface 19a on the outer circumference of the output shaft 2 and the split outer ring 4, releasing the frictional engagement between the outer circumference friction surface 16 of the split outer ring 4 and the inner circumference friction surface 15 of the fixed outer ring 3, and the output shaft 2 rotates together with the input shaft 1 in the other circumferential direction (left side in the diagram).

[0076] Here, when rotation is input to the output shaft 2 shown in Figure 5 (i.e., when reverse input is applied to the reverse input prevention clutch), instead of directly engaging the rollers 5a and 5b between the cam surfaces 19a and 19b on the outer circumference of the output shaft 2 and the inner circumference of the fixed outer ring 3, one side roller 5a or the other side roller 5b is engaged between the cam surfaces 19a and 19b on the outer circumference of the output shaft 2 and the split outer ring 4, and the rotation of the output shaft 2 is braked by frictionally engaging the partially annular outer friction surface 16 of the split outer ring 4 with the annular inner friction surface 15 of the fixed outer ring 3, so that the locking operation of the output shaft 2 is gradual. Similarly, when unlocking the output shaft 2, the friction engagement between the outer peripheral friction surface 16 of the split outer ring 4 and the inner peripheral friction surface 15 of the fixed outer ring 3 is released, allowing the output shaft 2 to rotate. This results in a gentler unlocking operation of the output shaft 2 compared to releasing the direct engagement of the rollers 5a and 5b between the cam surfaces 19a and 19b on the outer circumference of the output shaft 2 and the inner circumference of the fixed outer ring 3.

[0077] Furthermore, as shown in Figure 4, this reverse input prevention clutch is equipped with a rotational resistance loading mechanism (here, a preloading elastic member 26 and a thrust rolling bearing 27) that applies rotational resistance to the output shaft 2. Therefore, when rotation is applied to the input shaft 1 (see Figure 1) while there is no load on the output shaft 2, the force exerted by the roller 5a on the front side (right side in the figure) in the direction of rotation, as shown in Figure 6, against the cam surface 19a prevents the output shaft 2 from starting to rotate. Instead, the rotation is transmitted from the input shaft 1 to the output shaft 2 via the movable coupling part 23, allowing the output shaft 2 to start rotating. As a result, it is possible to prevent vibration from occurring when rotation is applied to the input shaft 1 while there is no load on the output shaft 2 (no-load state).

[0078] Furthermore, this reverse input prevention clutch employs a rotational resistance loading mechanism that applies rotational resistance with almost no wear, making it suitable for high-speed rotation applications. That is, as shown in Figure 4, it is also possible to employ a rotational resistance loading mechanism that applies rotational resistance to the output shaft 2, for example, by providing a sliding contact member that slides against the output shaft 2 and applying rotational resistance to the output shaft 2 through the friction of the sliding contact member. However, if a rotational resistance loading mechanism with such a configuration is adopted, wear of the sliding contact member progresses rapidly, making it unsuitable for high-speed rotation applications of the reverse input prevention clutch. In contrast, as shown in Figure 4, by employing a rotational resistance loading mechanism consisting of a preloading elastic member 26 incorporated in a state of elastic compression deformation in the axial direction, and a thrust rolling bearing 27 that applies the starting torque generated when the elastic restoring force of the preloading elastic member 26 is applied as rotational resistance to the output shaft 2, the starting torque of the rolling bearing is used as rotational resistance, resulting in almost no wear, making it possible to use the reverse input prevention clutch for high-speed rotation applications.

[0079] Furthermore, this reverse input prevention clutch is designed so that the magnitude of the rotational resistance applied to the output shaft 2 by the preloading elastic member 26 and thrust rolling bearing 27 shown in Figure 4 is greater than the circumferential biasing force acting on one roller 5a and the other roller 5b from the roller biasing spring 20 when the input shaft 1 (see Figure 1) is rotated relative to the output shaft 2 until the circumferential play of the free-moving coupling portion 23 is eliminated (i.e., the recess 24 contacts the convex portion 25), as shown in Figure 6. Therefore, when rotation is applied to the input shaft 1 in an unloaded state, it is possible to reliably prevent the output shaft 2 from starting to rotate due to the force of the front roller 5a (right side in the figure) pressing against the cam surface 19a before the recess 24 of the free-moving coupling portion 23 contacts the convex portion 25.

[0080] Furthermore, as shown in Figure 3, this reverse input prevention clutch has a boundary between adjacent circumferentially adjacent divided outer rings 4 that extends diagonally with respect to the axial direction, rather than parallel to the axial direction. This makes it possible to effectively suppress vibrations when one side roller 5a or the other side roller 5b, as shown in Figure 5, crosses over the boundary between the divided outer rings 4.

[0081] Furthermore, as shown in Figure 2, this reverse input prevention clutch has two or more rollers 5a on one side and two or more rollers 5b on the other side located radially inward of each divided outer ring 4. Therefore, when a reverse input torque acts on the output shaft 2, two or more rollers 5a on one side or two or more rollers 5b on the other side engage between the outer circumference of the output shaft 2 and the divided outer ring 4, and two or more rollers 5a (or 5b) that are spaced apart in the circumferential direction press one of the divided outer rings 4 radially outward. As a result, the frictional engagement between the outer circumference of the divided outer ring 4 and the inner circumference of the fixed outer ring 3 is stable when a reverse input torque acts on the reverse input prevention clutch.

[0082] Furthermore, as shown in Figure 1, this reverse input prevention clutch is provided with a centering section 14 between the shaft end of the input shaft 1 and the shaft end of the output shaft 2, which maintains the radial relative position of both shaft ends. This ensures that the axis of the input shaft 1 and the axis of the output shaft 2 are reliably aligned. As a result, the relative positional relationship between the one-sided cam surface 19a and the other-sided cam surface 19b shown in Figure 6 and the one-sided roller pressing section 22a and the other-sided roller pressing section 22b is stable, and the unlocking operation of the output shaft 2 is stable.

[0083] Furthermore, as shown in Figure 2, this reverse input prevention clutch uses the outer surface of the output shaft 2 as the one-sided cam surface 19a and the other-sided cam surface 19b, making it possible to form the one-sided cam surface 19a and the other-sided cam surface 19b with high precision at a low cost.

[0084] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0085] 1 input axis 2 Output shafts 3 Fixed outer ring 4-part outer ring 5a One-sided roller 5b Other side roller 6 Input side housing 7 Input side bearing 8 Output side housing 9 Output side bearing 14. Centering section 18 Circumferential end face 19a One-sided cam surface 19b Other side cam surface 20 Roller-driven spring 22a One-sided roller pressing section 22b Other side roller pressing section 23. Movable coupling section 26. Preloading elastic member (rotational resistance loading mechanism) 27. Thrust rolling bearing (rotational resistance load mechanism)

Claims

1. The input shaft (1) to which rotation is input, The output shaft (2) is rotatably supported coaxially with the input shaft (1), The annular fixed outer ring (3) surrounds the outer circumference of the output shaft (2), A plurality of segmented outer rings (4) are arranged in a circumferential direction along the inner circumference of the fixed outer ring (3), A plurality of one-sided rollers (5a) and a plurality of other-sided rollers (5b) are arranged alternately in the circumferential direction between the inner circumference of the plurality of divided outer rings (4) and the outer circumference of the output shaft (2), On the outer circumference of the output shaft (2), a plurality of one-sided cam surfaces (19a) that form a wedge-shaped space that narrows toward one side in the circumferential direction between them and the divided outer ring (4), and a plurality of other-sided cam surfaces (19b) that form a wedge-shaped space that narrows toward the other side in the circumferential direction between them and the divided outer ring (4) are alternately formed in the circumferential direction. The one-side roller (5a) is positioned between the one-side cam surface (19a) and the divided outer ring (4), and the other-side roller (5b) is positioned between the other-side cam surface (19b) and the divided outer ring (4). A roller biasing spring (20) is incorporated between the one-side roller (5a) and the other-side roller (5b) in a circumferentially compressed state, biasing the one-side roller (5a) and the other-side roller (5b) toward each other. The input shaft (1) is provided with a other-side roller pressing portion (22b) that moves together with the input shaft (1) when the input shaft (1) rotates in one direction in the circumferential direction to push the other-side roller (5b) in one direction in the circumferential direction, and a one-side roller pressing portion (22a) that moves together with the input shaft (1) when the input shaft (1) rotates in the other direction in the circumferential direction to push the one-side roller (5a) in the other direction in the circumferential direction. A movable connecting part (23) is provided between the input shaft (1) and the output shaft (2) to connect them with circumferential play. A reverse input prevention clutch is provided with a rotational resistance loading mechanism (26, 27) that loads a rotational resistance greater than the biasing force acting from the roller biasing spring (20) on one side roller (5a) and the other side roller (5b) onto the output shaft (2).

2. An input-side housing (6) is assembled to which an input-side bearing (7) that rotatably supports the input shaft (1) is fitted, The output side housing (8) is assembled to which an output side bearing (9) that rotatably supports the output shaft (2) is fitted, The reverse input prevention clutch according to claim 1, wherein the rotational resistance load mechanism (26, 27) comprises a preloading elastic member (26) incorporated in a state of elastic compression deformation in the axial direction, and a thrust rolling bearing (27) that loads the starting torque generated when the elastic restoring force of the preloading elastic member (26) is applied as the rotational resistance to the output shaft (2).

3. The reverse input prevention clutch according to claim 1 or 2, wherein the magnitude of the rotational resistance applied to the output shaft (2) by the rotational resistance load mechanism (26, 27) is set to be greater than the circumferential biasing force acting from the roller biasing spring (20) on the one-sided roller (5a) and the other-sided roller (5b) when the input shaft (1) is rotated relative to the output shaft (2) until there is no circumferential play in the free-moving coupling portion (23).

4. The reverse input prevention clutch according to claim 1 or 2, wherein the circumferential end face (18) of each divided outer ring (4) is an inclined surface with respect to the axial direction, such that the boundaries between adjacent divided outer rings (4) in the circumferential direction extend diagonally with respect to the axial direction.

5. The reverse input prevention clutch according to claim 1 or 2, wherein the circumferential length of each divided outer ring (4) is set such that two or more of the one-side rollers (5a) and two or more of the other-side rollers (5b) are located radially inward of each divided outer ring (4).

6. The reverse input prevention clutch according to claim 1 or 2, wherein a centering portion (14) is provided between the shaft end of the input shaft (1) and the shaft end of the output shaft (2) to maintain the radial relative position of both shaft ends.

7. Multiple planes are formed on the outer circumference of the output shaft (2), each having a shape obtained by cutting a part of the outer circumference of the output shaft (2) in a straight line, and are arranged in the circumferential direction. The reverse input prevention clutch according to claim 1 or 2, wherein the one-sided cam surface (19a) and the other-sided cam surface (19b) are a portion on one side in the circumferential direction and a portion on the other side in the circumferential direction, respectively, from the circumferential center of each plane.

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